Resistance in bacteria and indirect beta-lactamase detection in E. coli isolated from Culex pipiens detected by matrix-assisted laser desorption ionization time of flight mass spectrometry

The aim of this study was detections of antibiotic resistance and resistance mechanism in bacteria isolated from mosquitos (Culex pipiens) living near humans. Therefore, antibiotic resistance in bacteria isolated from Culex pipiens was investigated by disk diffusion test and MIC E-test in this study. MALDI-TOF mass spectrometry was used for detection of resistant mechanism. In this study, hydrolytic breakdown products after a few hours of incubation of the bacteria isolated from Culex pipiens were detected. Results show that enzymatic destruction of ampicillin by beta-lactamases is able to be detected by MALDI-TOF mass spectrometry from wild strains of potential pathogens. The MALDI-TOF mass spectrometry is useful method for routine detection of beta-lactamases resistant mechanism, but overnight incubation of pure culture is necessary. The results are important for proper and fast intervention to limit the spread of beta-lactamase-producing wild bacteria and provide information for appropriate initial therapy of the infections caused by these microbes.     

Multi-class determination of pharmaceuticals in wastewaters by solid-phase extraction and liquid chromatography tandem mass spectrometry with matrix effect study

Environmental Science and Pollution Research - In this work, a multi-class analytical method for determination of 22 frequently used pharmaceuticals was developed and validated. Analytes were from...     

Tributyltin chloride disrupts aortic vascular reactivity and increases reactive oxygen species production in female rats

Environmental Science and Pollution Research - Organotin compounds, such as tributyltin (TBT), are environment contaminants that induce bioaccumulation and have potential toxic effects on marine...     

Revisiting nitrous acid (HONO) emission from on-road vehicles: A tunnel study with a mixed fleet

Nitrous acid (HONO) is an important precursor of OH radicals in the atmosphere. In urban areas, emissions from vehicles are the main source of air pollutants, including reactive nitrogen. Previously reported emission ratios of HONO (HONO/NO_x) from vehicles were measured in the late 1990s and need to be updated due to the significant changes in emission control technologies. We measured the emission ratio of a fleet of vehicles (38% diesel on average) from March 11 to 21, 2015, in a road tunnel in Hong Kong. The emission ratio of 1.24% (±0.35%) obtained is greater than the commonly adopted 0.8% or 0.3%. The elevated emission ratio is found to be related to the presence of vehicles equipped with diesel particle filters (DPFs). Positive correlation between HONO and black carbon (BC) shows that HONO and BC were emitted together, while the lack of correlation or even anticorrelation between HONO/NO_x and BC indicates that the BC-mediated conversion of NO₂ to HONO in the dark was insignificant in the immediate vicinity of the emission sources.

Implications: Vehicular emission is a key source for HONO in the urban atmosphere. However, the most commonly used emission ratio HONO/NO_x in modeling studies was measured more than 15 years ago. Our tunnel study suggests that a mixed fleet nowadays has a higher emission ratio, possibly because of the diesel particle filter (DPF) retrofit program and the growing share of Euro IV or more advanced diesel vehicles. Our study also provides new insight into the role of black carbon in HONO formation from vehicles.     

Toxicity of new pyrethroid in pest insects Asciamonuste and Diaphania hyalinata,predator Solenopsis saevissima and stingless bee Tetragonisca angustula

There is increasing demand for new products for vegetable pest management. Thus, the aim of this study was to assess the toxicity of pyrethroids with acid moiety modifications to measure the insecticidal activity of these compounds on the lepidopteran vegetable pests Diaphania hyalinata (L.) (Lepidoptera: Pyralidae) and Asciamonuste (Latreille) (Lepidoptera: Pieridae) and evaluate their selectivity for the predatory ant Solenopsis saevissima (F. Smith) (Hymenoptera: Formicidae) and pollinator Tetragonisca angustula (Latreille) (Hymenoptera: Apidae: Meliponinae). Racemic mixtures of five new pyrethroids (30 µg molecule mg^?1 insect body weight) resulted in high (100%) and rapid (stable LD₅₀ after 12 h) mortality in D. hyalinata and A. monuste. In A. monuste, the trans-pyrethroid [12] isomer showed similar toxicity to permethrin. For D. hyalinata, the trans-pyrethroid [9] isomer and cis-pyrethroid [10] isomer were as toxic as permethrin. Due to their low selectivity, these new pyrethroids should be applied on the basis of ecological selectivity principles to minimize impacts on nontarget organisms S. saevissima and T. angustula.     

Identification of protein biomarkers of mercury toxicity in fish

Bioaccumulative metals such as mercury are found in increasing amounts in fish and their consumers. In the region of the Madeira River, in the Brazilian Amazon, mercury (Hg) is a predominant contaminant in the aquatic ecosystem. There is therefore a need to find specific biomarkers of mercury toxicity in fish to monitor contaminations. Here, mercury-bound proteins were identified in the liver tissues of fishes Mylossoma duriventre and Brachyplatystoma rousseauxii. Mercury was quantified in liver tissue, pellets and protein spots by graphite furnace atomic absorption. Proteins were fractionated by two-dimensional polyacrylamide gel electrophoresis and identified by mass spectrometry with electrospray ionization. We identified nine proteins linked to mercury and that presented biomarker characteristics of mercury. Among the proteins identified, isoforms of parvalbumin, ubiquitin-40S ribosomal protein S27a, brain-specific angiogenesis inhibitor 1-associated protein 2-like protein 2 and betaine–homocysteine S-methyltransferase 1 are notable for having the molecular function of binding to metallic ions.     

Supercritical fluid extraction of biofuels from biomass

A sustainable source of energy production can be provided using renewable resources. For instance, biomass is transformed into biofuels using several techniques such as supercritical fluid extraction, an effective thermochemical process. Here we review results on biofuels obtained from lignocellulosic and algal biomass using supercritical fluids. Biofuel yield and composition are controlled by operating conditions such as extraction temperature, pressure, biomass and solvent type, and the presence of catalysts. The extraction temperature is the major factor controlling biofuel yield. Biofuel yields can also be improved with the use of catalysts. Major compounds in biofuels from lignocellulosic biomass are phenols, catechols, guaiacols, syringols, syringaldehydes, syringyl acetone, acids, and esters. Most of these compounds are produced by lignin decomposition in lignocellulose. Furfural and derivatives are produced by the decomposition of cellulose and hemicellulose. Fatty acid alkyl esters are formed from lignin fragmentation by condensation of compounds bearing C–O or C=O. Prominent compounds in biofuels from algal biomass are saturated or unsaturated fatty acid alkyl esters.     

Land degradation a matter of attitude? A case study from southern Transylvania (Romania)

A better public perception and knowledge on land degradation increases the individual and collective responsibility in land use and land management. Based on interviews, this paper presents results of evaluation of public perception and attitude towards degrading phenomena in the central part of Romania, an area prone to geomorphologic processes, with different land uses and a high proportion of degraded land. The research reveals natural causes, improper land use, categories of land owned, socio-economic causes and involvement of institutions as key aspects of public perception. Our research could be useful in the identification and design of measures in regional planning to attract population in prevention, mitigation and rehabilitation actions on degraded land.     

Assessment of an appropriate integrated waste management plan targeting the Circular Economy based on the LCA method

Journal of Material Cycles and Waste Management - Rapid population growth and urbanization increase the Municipal Solid Waste (MSW) generation rate and the demand for natural resources. In order to...     

灌浆套筒连接预制拼装桥墩抗剪性能对比试验研究

灌浆套筒连接预制拼装桥墩抗弯性能得到了广泛研究,但抗剪性能研究较少.为对比分析灌浆套筒连接预制拼装桥墩抗剪性能,制作了2个相同缩尺比的现浇和预制拼装桥墩模型.通过拟静力方式测到了两类结构极限承载力、变形和耗能能力等抗震性能指标.对比分析结果表明,预制桥墩与现浇桥墩破坏模式存在显著差异,但是预制桥墩具备与现浇桥墩相近的耗...